Remember Mumia Abu-Jamal? He may derail Obama’s pick for top civil rights post.

Former Black Panther Mumia Abu-Jamal, who is serving life in prison for the 1981 killing of a white police officer. (Photo: Lisa Terry / Getty Images)

It's the cop-killing that won't go away.

More than 30 years have passed since the Mumia Abu-Jamal was convicted and sentenced to death for the killing of Philadelphia Police Officer Daniel Faulkner. But the case remains an internationally-known political lightning rod. And, this week, lightning is striking in D.C.

The latest incarnation of the Abu-Jamal trial comes as it threatens to derail the nomination of Debo P. Adegbile, President Obama's nominee to head the Justice Department's Civil Rights Division. He previously worked as legal counsel to the NAACP's Legal Defense Fund, which helped Abu-Jamal get his death sentenced overturned and has represented him at various points since.

While Adegbile's involvement with the Abu-Jamal case was limited -- and came well after the death sentence was tossed -- Faulkner's widow, the Fraternal Order of Police, and Sen. Pat Toomey (R-Pa.) have mounted a crusade to block the nomination. And recent development suggest they might prevail.

Under new Senate rules approved last November, Adegbile will need to secure a simple majority of senators -- 51 votes -- to clear a procedural hurdle before he is confirmed. But Adegbile's confirmation is at risk of falling short of the votes needed as Democrats face pressure from Republicans and several national law enforcement groups who oppose his nomination.

The first sign that the Adegbile nomination could be in real trouble came last week, when Sen. Bob Casey (D-Pa.) said he would not vote in favor of confirmation.

"The vicious murder of Officer Faulkner in the line of duty and the events that followed in the 30 years since his death have left open wounds for Maureen Faulkner and her family as well as the City of Philadelphia," Casey said in a statement. "After carefully considering this nomination and having met with both Mr. Adegbile as well as the Fraternal Order of Police, I will not vote to confirm the nominee."

Adegbile, 47, spent more than a decade working for the NAACP’s Legal Defense Fund, where he served as the group’s in-house voting rights expert. The legal defense fund began its work on Abu-Jamal's behalf well before Adegbile began working for it, however he did contribute to the filing of a 2009 court brief that argued that Abu-Jamal faced a discriminatory jury -- an appeal later found to have merit by a judge.

Several prominent Republicans are expected to take to the floor and speak in opposition to the nomination prior to Wednesday's vote -- which could put a number of Senate Democrats with difficult reelection campaigns in moderate and conservative states in a tough spot.

We asked spokespeople for each of them how they were planning to vote on Adegbile's nomination. As of early Tuesday afternoon, none had responded.

While Adegbile continues to come under attack by conservative and law enforcement groups, several prominent civil rights organizations and Democrats -- including the Congressional Black Caucus -- have come to his defense.

“Individuals in the media and in this Congress have worked to diminish and discredit Mr. Adegbile’s character and his record of defending the civil and constitutional rights of those in this country who need it most," said Rep. Marcia L. Fudge (D-Ohio), who leads the Congressional Black Caucus, in a statement released earlier Tuesday. "Every person should be able to exercise their constitutional right to legal representation, and we certainly cannot prevent attorneys from doing their best work on behalf of their clients. Mr. Adegbile should not be penalized or punished for either."

Adegbile's allies argue that his lengthy resume and legal career -- which includes twice defending the Voting Rights Act before the U.S. Supreme Court -- makes him the perfectly-qualified candidate for the post.

This only further complicates the vote for Democratic senators who are on the bubble.

Vote in favor of Adegbile's nomination and those senators could face a slew of attacks from conservative opponents during this fall's election. Vote against the nomination and potentially face the ire of their own caucus, undermine a major appointment of a Democrat president, and potentially anger traditionally-democratic African American voters who they need to turn out to retain their seats.